@RazorBladder: Working with a concept artist is fine, this will be considered as a team entry.
Your environment can be inspired by pre-existing concept, but try to go for an original take on this concept and not a pure reproduction. Creativity is key

I was thinking of having a couple of thrones in the throne room, as for a family of royals instead of a sole ruler. just wanted to make sure that this is okay?
Should the construction shot be for one of those thrones, or all of them?
As for the prizes, so if you are more interested in the team prizes, you just sign up with a team name instead of your username?

Multiple thrones is fine. construction shot could include one or all of them, your choice.
If you prefer the team prize, no worries! You'll be able to choose if you're one of the winners.

As for the construction shot, are you looking for an image file with multiple shots next to each other showing high poly, then low poly, then texture, then concept ... like a jpg. split in four squares?

As for the room, how strict is the definition of "room"? Does it need to have a ceiling? Could it be an exterior that is more of a throne area? Could it be section of a large building that has no ceiling as a design element? A ceiling but no walls?

As for the construction shot, are you looking for an image file with multiple shots next to each other showing high poly, then low poly, then texture, then concept ... like a jpg. split in four squares?

As for the room, how strict is the definition of "room"? Does it need to have a ceiling? Could it be an exterior that is more of a throne area? Could it be section of a large building that has no ceiling as a design element? A ceiling but no walls?

The construction shot presentation is up to you.
The "room" can be an open area yes, it can be more an "area" than a "room" if you prefer.

"3 beauty shots of the final environment taken from the real time engine of your choice."
What is this? the end result is not rendered pictures or what?
Also can i enter in a team and then another entry for just myself?

No offline renderer (VRay, Arnold, etc.), the final images must be taken from a real time engine (UE4, Toolbag2, Unity, etc.).
Only one entry per person is allowed, so you will have to choose between a team or a solo entry.

"Mission: Create a full fledged small to medium scale environment representing a Throne Room."
Does this mean we can create a full fleshed-out room (vaulted ceilings, chandeliers, etc.) on the scale of cm or inches, rather than real-world specifications (meters, feet)?

"Mission: Create a full fledged small to medium scale environment representing a Throne Room."
Does this mean we can create a full fleshed-out room (vaulted ceilings, chandeliers, etc.) on the scale of cm or inches, rather than real-world specifications (meters, feet)?

The unit scale is up to you. Scale in this context meant global scale of the scene, so that contestant wouldn't try to create huge environments that are too complicated to build and finish given the duration of the contest.

"A WIP (work-in-progress) thread must be made and maintained in the contest sub-forum for your discipline"

What is meant by discipline? In a team, are you looking for each member of the team to be following one discipline? or does each member need to have their own thread with assets they specifically made? or should it be one thread with each member posting assets as they are created?

Under General Rules on the contest overview page, it says winners will be announced on April 8th, but in the official rules it says April 15th, which day is actually being used for winner announcement?